Blade for a dry shaver



July 23, 1963 J, F, w 3,098,295

BLADE FOR A DRY SHAVER Filed Feb. 19, 1960 176 4 Jbhrz FIII'VVZEIIZOR' United States Patent 3,098,295 BLADE FGR A DRY SHAVER John F. Wahl, Sterling, 111., assignor to Wahl Clipper Corporation, Sterling, Ill, a corporation ot Illinois Filed Feb. 19, 1960, Ser. No. 9,991 3 Claims. (Cl. 3043) This invention relates to the movable blade in a dry shaver.

This application is a continuation-in-part application based on my prior, copending application Serial No. 535,570, which has matured into Patent No. 2,959,854 granted November 15, 1960, wherein the present subject matter was a non-elected species.

Dry shavers have at least one resilient fixed outer blade, and a cooperating movable inner blade powered by a vibratory motor. The vibratory motor generally has a pivotally mounted armature associated with the pole faces of the core, and the inner blade is connected to and driven by the free end of the armature. Since the free end of the pivoted armature moves in an arcuate path, the portion of the inner blade connected to this free end also moves in an arcuate path. Despite this, the cutting region of the inner blade must move along a substantially straight path in order to maintain proper contact with the cutting region of the outer blade.

In the past the inner movable blade was substantially rigid in character and was resiliently mounted in some manner so that as the portion of the blade connected to the free end of the armature moved along its arcuate path, the tendency of the inner blade to move out of contact with the fixed outer blade was compensated for by an in and out movement which resulted from the resilient mounting.

The rigidity of the inner blade, particularly at its connection with the free end of the armature, was desirable from the standpoint of durability. On the other hand the necessity of resiliently mounting the inner blade was objectionable because of the expense and additional parts required.

What is needed, therefore, and comprises an important object of this invention is an inner blade having one portion substantially rigid in character which is connected to the free end of the armature of the motor, and having a cutting region portion which can move in a straight path despite the arcuate movement of the portion of the blade connected to the armature.

This and other objects of this invention Will become more apparent when read in the light of the specification and the accompanying drawing wherein:

FIG. 1 is a plan view of a dry shaver embodying the invention with the cover of the casing and the outer blade removed showing the vibratory motor and its connection with the inner movable cutting blade.

FIG. 2 is a plan view of the inner movable cutting blade in initial fiat form with the mounting base omitted.

FIG. 3 is an enlarged sectional View taken on the line 33 of FIG. 1 and showing one form of inner movable cutting blade.

FIG. 4 is a dynamic view (somewhat exaggerated) showing the straight line vibratory movement of the cutting region of the inner blade and the arcuate movement of the portion connected to the armature.

FIG. 5 is a sectional view of a modified form of inner blade having an alternative base portion.

FIG. 6 is a sectional view on line 66 of FIG. 5.

Referring now to FIG. 1 of the drawing, a dry shaver indicated generally by the reference numeral 10 includes a vibratory electric motor 12 mounted in a casing section 14. Motor 12 has a magnetic core 16 and an armature 18 which is mounted for vibratory movement in association with the pole faces of the core in a manner well known in the art.

An inner movable blade 20 includes a portion 22 (FIG. 2) formed from initially flat sheet metal and attached base portions 24 and 25 (FIG. 3) formed from insulating material such as molded nylon. As best seen in FIG. 3, base portion 24 of the inner movable blade is attached to the free end 26 of armature 18 by means of bracket members 28 suitably secured to the opposite surfaces of free end 26 and base portion 24.

The sheet metal portion 22 of the blade, as shown in FIG. 2, includes a perforate cutting region 30, mounting holes 32, and diagonal slots 33 which introduce desired resilience and flexibility in the blade for reasons to become apparent below. In the embodiment shown, the initially fiat sheet metal portion 22 of the inner blade is bent to :a cylindrical shape and is attached to the base portions 24 and 25, see FIG. 3, but it is understood that the sheet metal may be bent into arcuate shapes other than cylindrical if desired. Projection '34 (FIG. 3) is one of two spaced projections on base portion 24- 'which pass through aligned mounting holes 32 of blade portion 22 and are received securely within apertures in base portion 25.

A fixed outer blade 35 of the shaver, shown in FIG. 3, is formed from thin resilient sheet metal. The perforate cutting portion or central region 37 of the outer blade is generally arcuate in cross section and is mounted on the casing so it presses against cutting portion 30 of the inner blade. Since part of the inner blade portion 22 is resilient and somewhat flexible due in part to diagonal slots 33, this engagement with outer blade 35 compresses the inner blade slightly and provides the desired cutting bias between the blades without requiring the inner blade to be resiliently mounted on the armature.

When the shaver is in operation, the base parts 24 and 25 of the inner blade 20 will travel with the free end 26 of the armature l8 along an arcuate vibratory path, but the tendency of the inner blade to move away from the outer blade during the end parts of its vibratory path will be compensated for by a decrease in compression of the inner blade. This will cause slight expansion of the blade so that its cutting region 36 will travel along substantially straight lines, see FIG. 4. In other words, the resilience and flexibility of the inner blade provides the transition necessary to permit the cutting region part of the blade to vibrate in a straight path and the base parts to vibrate along an arcuate path.

FIGS. 5 and 6 illustrate a modified form of inner blade 40 which comprises a thin, resilient sheet metal portion 42 and a base portion 44. Metal portion 42 has a pertorate cutting region 46, and both this region and the remainder of the metal portion have resilience and flexibility to provide the transition mentioned above.

Base portion 44 has a lower part 48 which is secured to free end 26 of armature 18 and an upper part 50 which is generally arcuate in cross section. A neck 52 connects lower part 48 and upper part 59. Base portion 44 may consist of molded plastic material or die cast metal.

As best shown in FIG. 6, neck 52 is provided on both sides with bosses 54, and metal portion 42 is provided with cooperating notches 56 in which the bosses are received. When this arrangement is used, metal portion 42 is bent permanently into desired arcuate shape, whereby the bosses and notches are eifective to maintain proper relationship between metal portion 42 and base portion 44.

The invention may be embodied in other forms without departing from the spirit or essential characteristics thereof as set forth in the claims, and the illustrated embodiments are therefore to be considered exemplary and not restrictive, and the invention is intended to include all changes which come within the scope of the claims.

I claim:

1. A blade for an electric shaver including a metal portion having a cutting region arcuate in cross section and a base portion, said base portion having a lower part, an upper part and a neck connecting said parts, a boss on each side of said neck, said metal portion having cooperating notches in which the bosses are received, at least a portion of said metal portion having resilience and flexibility to provide the transition necessary to permit the cutting region of the blade to move in a straight path while the base portion is moved along an arcuate path.

2. An inner cutting blade for a dry shaver comprising:

a cutting portion adapted for pressurized engagement with a fixed outer blade;

21 base portion remote from said cutting portion;

a resilient portion integral with said cutting portion and intermediate said cutting and base portions, said resilient portion mounted on said base portion;

said cutting and resilient portions formed of sheet metal having slots therein, the slots in said resilient portion inclined at an acute angle to the direction of blade travel; and

means adapted to connect said base portion to the free end of a pivotal armature whereby said base portion vibrates on an arcuate path, said resilient portion adapted to flex to permit said cutting portion to vibrate on the straight path defined by the fixed outer blade and to maintain said cutting portion in pressurized engagement with the fixed outer blade.

3. An inner cutting blade for a dry shaver comprising:

cutting portion of flexible perforated sheet metal adapted for pressurized engagement with a fixed outer blade;

a drivable portion remote from said cutting portion;

a resilient portion of flexible sheet metal integral with and of the same thickness as said cutting portion and intermediate said cutting and drivable portions, said resilient portion connected to said drivable portion; and

means adapted to connect said drivable portion to the free end of a pivotal armature whereby said drivable portion vibrates on an arcuate path, said resilient portion adapted to flex to permit said cutting portion to vibrate on the straight path defined by the flexed outer blade and to maintain said cutting portion in pressurized engagement with the fixed outer blade.

References Cited in the file of this patent UNITED STATES PATENTS 2,164,425 Rand July 4, 1939 2,178,669 Lougheed Nov. 7, 1939 2,181,038 Wimberger Nov. 21, 1939 2,242,405 Sussman May 20, 1941 2,265,932 Wahl Dec. 9, 1941 2,281,434 Gur Arye Apr. 28, 1942 2,306,172 Lindholm Dec. 22, 1942 2,335,607 Penney Nov. 30, 1943 2,601,720 Carissirni July 1, 1952 2,900,719 Kohner et al Aug. 25, 1959 2,915,816 Gray Dec. 8, 1959 2,950,530 Fox Aug. 30, 1960 FOREIGN PATENTS 580,032 Great Britain Aug. 23, 1946 

1. A BLADE FOR AN ELECTRIC SHAVER INCLUDING A METAL PORTION HAVING A CUTTING REGION ARCUATE IN CROSS SECTION AND A BASE PORTION HAVING A LOWER PART, AN UPPER PART AND A NECK CONNECTING SAID PARTS, A BOSS ON EACH SIDE OF SAID NECK, SAID METAL PORTION HAVING COOPERATING NOTCHES IN WHICH THE BOSSES ARE RECEIVED, AT LEAST A PORTION OF SAID METAL PORTION HAVING RESILIENCE AND FLEXIBILITY TO PROVIDE THE TRANSITION NECESSARY TO PERMIT THE CUTTING REGION OF THE BLADE TO MOVE IN A STRAIGHT PATH WHILE THE BASE PORTION IS MOVED ALONG AN ARCUATE PATH. 